Appendicectomy in Western Australia: profile and trends, 1981-1997

Objective: To measure and describe changes in the incidence of appendicecto my in the population of Western Australia (WA) for 1981-1997. Design: Population-based incidence study using hospital discharge data. Setting: All hospitals in WA (1981-1997). Patients: All patients who underwent an appendicectomy in WA hospitals. Main outcome measures: Changes in the incidence of appendicectomy procedure s over time; age-standardised rates and age-sex profiles of four appendicec tomy subgroups: (1) acute emergency admission, (2) other emergency admissio n, (3) incidental appendicectomy and (4) other appendicectomy. Results: From 1981 to 1997, there were 59 749 appendicectomies in WA hospit als. The age-standardised rate of appendicectomy declined by 63% in metropo litan females, by 44% in non-metropolitan females, by 41% in metropolitan m ales and by 21% in non-metropolitan males. The rate of decline was signific antly greater in females and in metropolitan patients. From 1988 to 1997, a cute emergency admission for appendicectomy was the most common admission s tatus and was more common in males than females (122 v 103 per 100 000 pers on-years) and in non-metropolitan areas. The rate of incidental appendicect omy was higher among females than males (20 v 7 per 100 000 person-years). From 1988 to 1997, recorded diagnosis coding for appendicitis became more s pecific, with a marked reduction in the use of the "unspecified" appendicit is code. Conclusions: The overall incidence of appendicectomy has declined markedly in WA and includes a decline in the practice of incidental appendicectomy. The trend was greatest in the metropolitan hospitals.